Motion picture camera

ABSTRACT

The shutter of a motion picture camera has a surface which reflects light against a photosensitive element when the shutter covers the film aperture. That portion of such surface which covers the aperture when the shutter is at rest reflects part of the light onto the photosensitive element and the remainder of the light in another direction. In this way, the amount of light received by the photosensitive element when the shutter is at rest is the same as the average amount of light reaching the photosensitive element when the shutter is in motion. The shutter may be of the rotary or reciprocatory type and its lightreflecting surface may be formed by a foil or by a coat of suitable reflecting material.

picture camera has a perture. That portion of y the photosensitiveelethe ry or reflecting surface may be FOREIGN PATENTS 243,088 l0/l955Austria..... 41,467 9/1965 Germany......................

OTHER REFERENCES Schafer, German Printed Application No. 1,221.097, .Iul14,1966,(KL57a-43), 352/141 Primary Examiner-Samuel 5. MatthewsAssistant Examiner-Joseph F. Peters, .1 r. Attorney-Michael S. StrikerABSTRACT: The shutter of a motion surface which reflects light against aphotosensitive element when the shutter covers the film a such surfacewhich covers the aperture when the shutter is at rest reflects part ofthe light onto the photosensitive element and the remainder of the lightin another direction. ln this way, the amount of light received b mentwhen the shutter is at rest is the same as the avera amount of lightreaching the photosensitive element when shutter is in motion. Theshutter may be of the rota reciprocatory type and its lightformed by afoil or by a coat of suitable reflecting material.

ll'lllll)llll" Inventor Theo Wilharm Endersbach, Germany Applt Nov657.906 Filed Aug. 2. 1967 [45] Patented Aug. 3,1971

Assignee Robert Bosch Photokino Gmbl-l Stuttgart-Untertuerkheim. GermanyPriority Aug. 27, 1966 Germany 888,666

Morton Prcruru: CAMERA 15 Claims, 8 Drawing Figs.

Field 64; 352/141, 208

References Cited UNITED STATES PATENTS 9/1965Koeber.........................

United States Patent PATENTED AUG 3am SHEET 1 UF 2 his A 77 ORNE YPAIENIEU AUG 3191:

ilIIIIII lNVf/VTOR.

THE 0 W/LHARM his A TTURNE Y MOTION PICTURE CAMERA BACKGROUND OF THEINVENTION The present invention relates to motion picture cameras ingeneral, and more particularly to improvements in motion picture cameraswherein a shutter moves cyclically between the objective and the filmaperture to admit light to the film when the latter is stationary and tocover the aperture when the film is being advanced by the length ofaframe. Still more particularly, the invention relates to improvements inmotion picture cameras wherein the shutter reflects light onto aphotosensitive element which is connected in circuit with a moving coilinstrument serving to indicate the intensity of scene light and/or tocontrol an automatic diaphragm.

In motion picture cameras of thcjust outlined character, thephotosensitive element receives light when the shutter is idle as wellas when the shutter performs cyclic movements so that the moving coilinstrument can indicate the intensity of scene light. This enables theoperator to determine the intensity at all times, and the moving coilinstrument can automatically change the size of the diaphragm openingwhen the camera is in use. However, when the shutter is in motion, theamount of light which reaches the photosensitive element fluctuates butsuch fluctuations do not affect the position of the needle in the movingcoil instrument because the latter's inertia prevents it from changingthe position of the needle at the same frequency at which the shutterperforms its cyclic movement. As a rule, the setting of a diaphragmwhich is controlled by the moving coil instrument is lower when theshutter moves than when the shutter is in the position of rest despitethe fact that the intensityrof scene light remains unchanged.

In order to compensate for such differences in the amounts of lightwhich reach the photosensitive element when the latter respectivelyreceives reflected light from a stationary or a moving shutter, certainmotion picture cameras are provided with a resistor which is connectedin the circuit of the moving coil instrument when the shutter actuatingtrigger is released (see German Pat. No. 1,067,303). Such arrangement isoverly sensitive and complicated because its reliability depends on thedesign of the switch which controls the resistor and on the effect oftemperature upon the resistor. It was found that the moving coilinstruments of such cameras become unreliable after extended periods ofuse and when the operating conditions deviate from normal.

In accordance with another prior proposal (German Pat. No. l,094,585),the reflectivity ofa portion of the surface on the shutter is lessenedby the application of a light-absorbing coat which is in registry withthe objective when the shutter is idle. The composition, application andcharacteristics of such light-absorbent coats must be selected with avery high degree of accuracy, and the coats must be applied by resortingto complicated machinery and by employing highly skilled persons.Furthermore, it is very difficult to mass-produce such shutters withoutany changes in the light-reflecting and lightabsorbent characteristicsof their surfaces.

US. Pat. No. 3,248,166 to Reinsch proposes the utilization of an opaquemask which is moved into the light path when the shutter is idle toreduce the amount of light so that the average amount of light reachingthe photosensitive element in the exposure control is the sameregardless of the condition of the shutter. The mask is connected withthe shutter release and is automatically withdrawn from the light pathwhen the shutter is set in motion. This solution is satisfactory but themask occupies additional room and must be mechanically or otherwisecoupled to the shutter release.

SUMMARY OF THE INVENTION It is an object of my invention to provide anovel and improved motion picture camera wherein the shutter can directto the photosensitive element requisite amounts of light irrespective ofwhether the shutter is in motion or in the position of rest and whereinsuch distribution of light can be carried out without necessitating theprovision of any additional parts, such as resistors, masks, opaquecoatings or the like.

Another object of the invention is to provide a motion pic ture cameraof the just outlined type wherein the shutter can be mass-produced atlow cost and in such a way that each of a large number of seriallyproduced shutters will exhibit identical light-reflectingcharacteristics.

A further object of the invention is to provide a novel blade which canbe used as a part of a rotary or reciprocatory shutter for motionpicture cameras.

An additional object of the instant invention is to provide a motionpicture camera wherein the shutter occupies the same amount of space oreven less than in presently known motion picture cameras.

A concomitant object of my invention is to provide a light measuringstructure for motion picture cameras which is capable of measuring thelight passing through the objective of the camera in such a way thatproper compensation will be made for the fact that the aperture iscyclically covered and uncovered by the shutter.

An ancillary object of the invention is to provide a motion picturecamera which can measure light passing through the objective when theshutter is at rest in such a way that the measurement will correspondwith requisite accuracy to the measurement when the camera is inoperation.

My invention is embodied in a motion picture camera which comprises anobjective, means defining a light-admitting aperture behind the opticalaxis of the objective, a photosensitive element which may constitute aresistor or a cell, and novel shutter means moving cyclically betweenthe objective and the aperture for covering and uncovering the apertureduring each cycle so that the film is exposed only when the aperture isuncovered. The shutter means has a position of rest when the aperture iscovered and is provided with a light-reflecting surface which reflectslight received from the objective when the aperture is covered. Thelight-reflecting surface has a first portion which reflects light ontothe photosensitive element when the shutter means is in motion but stillcovers the aperture and a second portion which, when the shutter meansis in the position of rest, reflects a first amount of light onto thephotosensitive element and reflects a second amount of light in adirection other than toward the photosensitive element.

Each portion of the light-reflecting surface may be composed of severalstripor band-shaped sections whereby all such sections of the firstportion reflect light onto the photosensitive element whereas only someof the sections in the second portion reflect light onto suchphotosensitive element.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theimproved motion picture camera itself, however, both as to itsconstruction and its mode of operation, together with additionalfeatures and advantages thereof, will be best understood upon perusal ofthe following detailed description of certain specific embodiments withreference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a fragmentary longitudinalvertical sectional view of a motion picture camera with a rotary shutterwhich embodies one form ofmy invention;

FIG. 2 is a larger scale front elevational view of the shutter as seenin the direction ofthe arrow II in FIG. 1;

FIG. 3 is an enlarged fragmentary sectional view of the shuttersubstantially as seen in the direction of arrows from the line Ill-lllof FIG. 2;

FIG. 4 is a similar fragmentary sectional view of the shuttersubstantially as seen in the direction of arrows from the line IV-IV ofFIG. 2;

FIG. 5 is a fragmentary longitudinal vertical sectional view of a secondmotion picture camera with a modified rotary shutter;

FIG. 6 is a fragmentary front elevational view of the modified shuttersubstantially as seen in the direction of the arrow VI in FIG.

FIG. 7 is a fragmentary longitudinal vertical sectional view of a thirdmotion picture camera with a reciprocatory shutter;

and

FIG. 8 is a front elevational view of the shutter substantially as seenin the direction of the arrow VIII of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1,there is shown a portion of a motion picture camera comprising a housingor body 1 whose front wall 2 carries an objective 3. An internalpartition or wall 4 of the housing I is provided with a window oraperture 5 which is located behind the optical axis of the objective 3and admits light to the motion picture film 6. The film is advancedstepwise in a manner well known from the art of motion picture cameras.The pulldown which effects such stepwise movements ofthe film 6 is notshown in the drawings.

A rotary shutter 7 is installed in the space between the walls 2 and 4.This shutter comprises a hub 70 (see FIG. 2) and a blade 14 whichextends along an arc of 180. The function of the shutter 7 is tointermittently interrupt the passage of light from the objective 3 tothe film 6, always at the time when the film is being advanced by thelength ofa frame. The hub 7a is rigid with a shaft 8 which is journaledin the partition 4 and in a further intermediate wall 9 of thehousing 1. This shaft 8 forms part of a drive which further includes anelectric motor 10 and a transmission including a first pinion 11 on theoutput shaft of the motor 10, a second pinion 13 on the shaft 8, and anendless toothed belt 12 or the like which is trained around the pinionsl1 and 13.

The front side of the blade 14 (i.e., that side which faces theobjective 3) is mirrored, for example, by the provision of a thinmetallic foil or another coat of light-reflecting material. When theshutter 7 is in a position of rest (shown in FIG. 2), a portion 20 ofthe light-reflecting surface 15 on its blade 14 is located between theobjective 3 and the aperture 5. The purpose of the light-reflectingsurface 15 is to direct controlled amounts of light against aphotosensitive element 16 which is installed in the space between thewalls 2 and 4 and is electrically connected with the moving coilinstrument 19 of an auto-' matic exposure meter by means of conductorsI7, 18. The instrument 19 may be used to merely indicate the intensityof scene light or to control an automatic diaphragm in a manner wellknown from the art of motion picture cameras. The lightreflectingsurface 15 of the blade 14 includes the aforementioned portion 20 and atwo-part portion 15A which includes a series ofelongated arcuatesections 15al5fshown in FIG. 3. The sections l5a-I5fare inclined withreference to the optical axis 3a of the objective 3 and are stepped asseen in the radial direction of the shutter 7. The inclination of all ofthe sections Isa-15f is the same. Fig. 3 shows that these sectionsreflect light coming from the objective 3 against the light-sensitivesurface of the photosensitive element 16 when the shutter 7 rotates andis in a position other than that in which the blade 14 permits light toreach the aperture 5 and film 6. In the illustrated embodiment, theelement 16 is a photoelectric cell and the output member or needle 19aof the moving coil instrument 19 indicates the strength of thephotocurrent.

The portion 20 of the reflecting surface 15 comprises alternatingelongated arcuate light-reflecting sections l5al5f' and 15a"-l5f", seeFIG. 4. When the shutter 7 is in the posi tion of rest (FIG. 2), thesections l5a'-l5f' reflect a certain amount of light onto thephotosensitive element 16 but the inclination of sections 15a"--l5f" issuch that they reflect the remaining light in a direction other thanagainst the element 16. The inclination of sections 15a-15f' withreference to the optical axis 3a is the same as that ofthe sections15u-I5f. The inclination of the sections I5a"l5j is such that theyreflect light back toward the objective 3. The combined width of one ofthe sections l5a'l5f' and the associated section 15a-l5f (as consideredin the radial direction of the blade 14) is the same as the width of therespective section 15a- 15f. This is shown in FIG. 2. The planes ofthesections 15a"- 15/" are normal or nearly normal to the optical axis 3a.Thus, when the shutter 7 is in the position of rest, the photosensitiveelement 16 receives only that amount of light which is reflected on thesections l5a'-l5f, i.e., less light than when the blade 14 maintains theportion 15A of its surface 15 between the aperture 5 and objective 3.Light reflected by the sections l5a15j' forms on the light-sensitivesurface of the element 16 a regular pattern of illuminated strips whichalternate with darker strips caused by the sections 15al3 15f. Theratioof the combined area of sections 15a'-l5f' to the combined area ofsections 15a15f" is such that, when the shutter 7 is in the position ofrest, the element 16 receives the same amount of light as the averageamount of light reflected by the sections 15a-l5f and 15a'15f' when theshutter rotates. In other words, the strength of the photocurrentgenerated by element 16 is the same, regardless ofwhether the shutterrotates or assumes the position of rest.

FIGS. 5 and 6 illustrate a portion ofa second motion picture cameraincluding a rotary shutter 22 which is mounted on a drive shaft 21. Theblade 23 of the shutter 22 resembles a portion of a smooth surfacedconical frustum. That surface 24 of the blade 23 which faces theobjective 3 reflects light and is preferably formed by the exposedsurface of a metallic foil or another coat of suitable reflectingmaterial which can be sprayed or otherwise applied to the blade 23. Theinclination of the surface 24 is such that it can reflect light onto aphotosensitive element 25 which is connected with a moving coilinstrument 28 by means of conductors 26, 27. The blade 23 can rotate ina plane which is located between the objective 3 and the aperture 5, thelatter being provided in the wall 4 in front of the motion picture film6.

That portion 241: of the surface 24 which is located between theobjective 3 and the aperture 5 when the shutter 22 is in the position ofrest (shown in FIG. 6) is inclined with reference to the optical axis 3ain such a way that it reflects only half of the total amount of incominglight against the light-sensitive surface of the element 25. This isshown in FIG. 5 by phantom lines. The remaining portion of the surface24 (which is located between the objective 3 and the aperture 5 when theshutter 22 rotates and is not in the position of rest or in the positionin which light can reach the film 6) is inclined with reference to theoptical axis 3a in such a way that it directs onto the element 25 morelight than the surface portion 24a. For example, the remaining portionof the surface 24 can reflect all of the incoming light against theelement 25. The portion 24a performs the same function as the sections15a- 151" and 15a"l5f" of the surface portion 20 in the embodiment ofFIGS. 1 to 4. When the shutter 22 is in the position of rest, theelement 25 receives the same amount of light as the average amount whenthe shutter rotates.

Referring to FIGS. 7 and 8, there is shown a portion of a third motionpicture camera which comprises a reciprocating shutter 29. The drive forthe shutter 29 includes a disk 30 driven by a shaft 31 and having aneccentric crank pin 32 which extends into an elongated vertical slot 33provided in a downward extension 29a of the shutter 29. The shutterfurther comprises two eyes or followers 34, 35 which are slidable alonga horizontal guide rod 35 mounted on the wall 104 of the camera housing.The aperture is shown at 105, the objective at 3, and the film at 6.When the shaft 31 is driven by the motor (not shown in FIGS. 7 and 8),the pin 32 causes the shutter 29 to travel back and forth along theguide rod 36 and to respectively cover and uncover the aperture 105.FIG. 8 shows the shutter 29 in the position of rest in which a portionof its blade 39 extends across the space between the objective 3 andaperture 105. The front side of the blade 39 is provided with alight-reflecting surface 37. This surface includes a portion whichcovers the aperture part of the time when the shutter 29 is in motionand which includes four straight equidistant parallel striporband-shaped sections 37a37d corresponding substantially to the sectionsl5al5f. These sections are inclined with reference to the optical axisof the objective 3 to the same extent and are arranged in stepwisefashion (see FIG. 7). Their purpose is to reflect light onto aphotosensitive element 38 which can be connected with a moving coilinstrument in the same way as shown in FIG. 1 or 5.

That portion of the surface 37 on the blade 39 which is located in frontof the aperture 105 when the shutter 29 is at rest comprises straightstrip-shaped sections 37a3 7d alternating with straight stripshapedsections 37l"-37 The combined height of the sections 37a and 37a" equalsthe height of the section 37a. The same holds true for the sections37b'3 7d, 37b"- 37d" and 37b37d. The sections 37a- 37d are inclined inthe same way as the sections 37u-37d and serve to direct light againstthe photosensitive element 38. The sections 37a37 reflect light backtoward the objective 3 in the same way as the sections l5a-l5f", i.e.,the planes of the sections 37a-37 are normal to the axis 3a. The ratioof the amounts of light reflected by the sections 37a-3 7d when theshutter 29 is in the position of rest to the average amounts of lightreflected by the sections 37u-37d when the shutter reciprocates isselected in such a way that the average amount of light received by theelement 38 remains unchanged regardless of whether the shutter is inmotion or not. Thus, the needle of the moving coil instrument which isconnected in circuit with the element 38 will remain at a standstill, aslong as the intensity of scene light is unchanged.

The shutter 7, 22 or 29 preferably consists of a single piece ofsynthetic plastic material which can be formed by injection molding orin accordance with another suitable plastic processing method. Thus, theshutter can receive its final form during shaping so that itsmanufacture involves little cost. The one-piece plastic article is thenprovided with a thin coat of light-reflecting material to form thesurface 15, 24 or 37.

It is clear that the improved motion picture camera is susceptible ofmany additional modifications without departing from the spirit of myinvention. For example, the sections of the light-reflecting surfaceneed not resemble strips or bands and need not be distributed withutmost uniformity. The reflecting surface may resemble a checkerboardwith small mutually inclined rectangular fields.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featureswhich from the standpoint of prior art fairly constitute essentialcharacteristics ofthe generic and specific aspects of my contribution tothe art and, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims.

lclaim:

1. In a motion picture camera, a combination comprising an objective;means defining a light-admitting aperture behind the axis of saidobjective; photosensitive means; and shutter means moving cyclicallybetween said objective and said aperture for covering and uncoveringsaid aperture during each cycle so that the film is exposed only whensaid aperture is uncovered, said shutter means having a rest positioncovering said aperture and being provided with a light-reflectingsurface which reflccts light received from said objective when saidaperture is covered, said surface having a first portion which reflectslight onto said photosensitive means when the shutter means is in motionbut still covers said aperture and a second portion which, when theshutter means is in said rest position, reflects a first amount of lightonto said photosensitive means and reflects a second amount oflight in adirection other than toward said photosensitive means.

2. A combination as defined in claim 1, wherein said shutter meanscomprises a single piece of synthetic plastic material having a sidefacing said objective and provided with a thin coat oflightreflectingmaterial forming said surface.

3. A combination as defined in claim 1, wherein said surface portionsare of arcuate shape.

4. A combination as defined in claim 1, wherein said shutter means isrotatable about a fixed axis and further comprising drive means for saidshutter means.

5. A combination as defined in claim 1, wherein said shutter means isreciprocable between said objective and said aperture, and furthercomprising drive means for reciprocating said shutter means.

6. A combination as defined in claim 1, wherein at least one portion ofsaid surface is stepped.

7. A combination as defined in claim 1, wherein said shutter meanscomprises a blade and said surface is provided on said blade.

8. A combination as defined in claim 1, wherein said photosensitivemeans forms part of an automatic diaphragm.

9. A combination as defined in claim 1, wherein said surface is arrangedto reflect light upwardly in normal position of the camera.

10. In a motion picture camera, a combination comprising an objective;means defining a light-admitting aperture behind the axis of saidobjective; photosensitive means; and shutter means moving cyclicallybetween said objective and said aperture for covering and uncoveringsaid aperture during each cycle so that the film is exposed only whensaid aperture is uncovered, said shutter means having a rest positioncovering said aperture and being provided with a light-reflectingsurface which reflects light received from said objective when saidaperture is covered, said surface having a first portion which reflectslight onto said photosensitive means when the shutter means is in motionbut still covers said aperture and a second portion which, when theshutter means is in said rest position, reflects a first amount of lightonto said photosensitive means and reflects a second amount oflight in adirection other than toward said photosensitive means, the first portionof said surface comprising sections having a predetermined inclinationwith reference to said axis and arranged to reflect light onto saidphotosensitive means and the second portion of said surface having firstsections having the same inclination as the sections of said firstportion and arranged to reflect said first amount of light and secondsections whose inclination is different from said predeterminedinclination so that said second sections reflect said second amount oflight.

11. A combination as defined in claim 10, wherein said first and secondsections are distributed uniformly in the second portion of saidsurface.

12. A combination as defined in claim 10, wherein said second sectionsalternate with said first sections.

13. A combination as defined in claim 10, wherein said sections resembleelongated strips.

14. In a motion picture camera, a combination comprising an objective;means defining a light-admitting aperture behind the axis of saidobjective; photosensitive means; and shutter means moving cyclicallybetween said objectiveand said aperture for covering and uncovering saidaperture during each cycle so that the film is exposed only when saidaperture is uncovered, said shutter means having a rest positioncovering said aperture and being provided with a light-reflectingsurface which reflects light received from said objective when saidaperture is covered, said surface having a first portion which reflectslight onto said photosensitive means when the shutter means is in motionbut still covers said aperture and a second portion which, when theshutter means is in said rest position, reflects a first amount of lightonto said photosensitive means and reflects a second amount of light ina direction other than toward said photosensitive means, the entirefirst portion of said surface having a predetermined inclination withreference to said axis and the entire second portion of said surfacehaving a different inclination with reference to said axis.

15. In a motion picture camera with exposure measurement, an objectivelens, a picture window, a movable window shutter carrying a mirrorarranged between said objective lens and said-picture window and facingsaid objective lens, said mirror being so inclined to the axis of saidobjective lens that during the dark period of the film it deflects allof the light normally illuminating the picture window to a photoelectricconverter to be used as measurement and control light, and a smallreflector inclined to the deflecting face of said mirror and disposed onthat portion of said mirror which in the still condition of the saidshutter is arranged in axial alignment with said objective lens, saidsmall reflector deflecting a part of the exposure light passing throughsaid objective lens past said photoelectric converter, the arrangementbeing such that the light beam illuminating the picture window duringpicture taking is deflected in the direction ofthe movement of saidmirror so that shortly before and after said shutter reaches its stillposition additional light is deflected onto the receiving surface of thephotoelectric converter from that portion of the light beam passingthrough said objective lens which in all other possible mirror positionsis not used for measuring the light at the picture window.

1. In a motion picture camera, a combination comprising an objective;means defining a light-admitting aperture behind the axis of saidobjective; photosensitive means; and shutter means moving cyclicallybetween said objective and said aperture for covering and uncoveringsaid aperture during each cycle so that the film is exposed only whensaid aperture is uncovered, said shutter means having a rest positioncovering said aperture and being provided with a light-reflectingsurface which reflects light received from said objective when saidaperture is covered, said surface having a first portion which reflectslight onto said photosensitive means when the shutter means is in motionbut still covers said aperture and a second portion which, when theshutter means is in said rest position, reflects a first amount of lightonto said photosensitive means and reflects a second amount of light ina direction other than toward said photosensitive means.
 2. Acombination as defined in claim 1, wherein said shutter means comprisesa single piece of synthetic plastic material having a side facing saidobjective and provided with a thin coat of light-reflecting materialforming said surface.
 3. A combination as defined in claim 1, whereinsaid surface portions are of arcuate shape.
 4. A combination as definedin claim 1, wherein said shutter means is rotatable about a fixed axisand further comprising drive means for said shutter means.
 5. Acombination as defined in claim 1, wherein said shutter means isreciprocable between said objective and said aperture, and furthercomprising drive means for reciprocating said shutter means.
 6. Acombination as defined in claim 1, wherein at least one portion of saidsurface is stepped.
 7. A combination as defined in claim 1, wherein saidshutter means comprises a blade and said surface is provided on saidblade.
 8. A combination as defined in claim 1, wherein saidphotosensitive means forms part of an automatic diaphragm.
 9. Acombination as defined in claim 1, wherein said surface is arranged toReflect light upwardly in normal position of the camera.
 10. In a motionpicture camera, a combination comprising an objective; means defining alight-admitting aperture behind the axis of said objective;photosensitive means; and shutter means moving cyclically between saidobjective and said aperture for covering and uncovering said apertureduring each cycle so that the film is exposed only when said aperture isuncovered, said shutter means having a rest position covering saidaperture and being provided with a light-reflecting surface whichreflects light received from said objective when said aperture iscovered, said surface having a first portion which reflects light ontosaid photosensitive means when the shutter means is in motion but stillcovers said aperture and a second portion which, when the shutter meansis in said rest position, reflects a first amount of light onto saidphotosensitive means and reflects a second amount of light in adirection other than toward said photosensitive means, the first portionof said surface comprising sections having a predetermined inclinationwith reference to said axis and arranged to reflect light onto saidphotosensitive means and the second portion of said surface having firstsections having the same inclination as the sections of said firstportion and arranged to reflect said first amount of light and secondsections whose inclination is different from said predeterminedinclination so that said second sections reflect said second amount oflight.
 11. A combination as defined in claim 10, wherein said first andsecond sections are distributed uniformly in the second portion of saidsurface.
 12. A combination as defined in claim 10, wherein said secondsections alternate with said first sections.
 13. A combination asdefined in claim 10, wherein said sections resemble elongated strips.14. In a motion picture camera, a combination comprising an objective;means defining a light-admitting aperture behind the axis of saidobjective; photosensitive means; and shutter means moving cyclicallybetween said objective and said aperture for covering and uncoveringsaid aperture during each cycle so that the film is exposed only whensaid aperture is uncovered, said shutter means having a rest positioncovering said aperture and being provided with a light-reflectingsurface which reflects light received from said objective when saidaperture is covered, said surface having a first portion which reflectslight onto said photosensitive means when the shutter means is in motionbut still covers said aperture and a second portion which, when theshutter means is in said rest position, reflects a first amount of lightonto said photosensitive means and reflects a second amount of light ina direction other than toward said photosensitive means, the entirefirst portion of said surface having a predetermined inclination withreference to said axis and the entire second portion of said surfacehaving a different inclination with reference to said axis.
 15. In amotion picture camera with exposure measurement, an objective lens, apicture window, a movable window shutter carrying a mirror arrangedbetween said objective lens and said picture window and facing saidobjective lens, said mirror being so inclined to the axis of saidobjective lens that during the dark period of the film it deflects allof the light normally illuminating the picture window to a photoelectricconverter to be used as measurement and control light, and a smallreflector inclined to the deflecting face of said mirror and disposed onthat portion of said mirror which in the still condition of the saidshutter is arranged in axial alignment with said objective lens, saidsmall reflector deflecting a part of the exposure light passing throughsaid objective lens past said photoelectric converter, the arrangementbeing such that the light beam illuminating the picture window duringpicture taking is deflected in the direction of the movemenT of saidmirror so that shortly before and after said shutter reaches its stillposition additional light is deflected onto the receiving surface of thephotoelectric converter from that portion of the light beam passingthrough said objective lens which in all other possible mirror positionsis not used for measuring the light at the picture window.